The present invention relates to an apparatus and method for the photodynamic therapy treatment of acne vulgaris and seborrhea and, more particularly, to a violet/blue light radiating system that illuminates a collimated narrow bandwidth beam on the treated skin area. The method relates to the combined photodynamic skin treatment including narrow band violet/blue light radiation and topical application of oxidative and/or keratolytic agents.
The enlargement and obstruction of sebaceous glands cause acne vulgaris. Due to the accumulation of sebum in the glands, bacteria, mainly propionibacterium acnes (p. acnes), proliferate in the glands. These bacteria cause inflammation and later the formation of pustular lesions and acne cysts, which heal by scarring.
It is known that p. acnes produce porphyrins. It is also known that visible light in the violet/blue (405-410 nanometer range), or less efficiently, red (630-670 nanometer range) are able to induce a photodynamic effect in which the porphyrins in the enlarged sebaceous glands react with oxygen to form peroxides. These peroxides are short-lived toxic compounds that are able to eliminate, or considerably diminish, the number of bacteria in the glands.
Photodynamic therapy (PDT) is based on the optimal interaction of four elements; light, photosensitizer, oxygen and skin penetration. Prior patents and publications related to acne phototherapy dealt only with the first two elements of PDT, i.e., and light exposure and sebaceous gland porphyrins. Studies have shown that the photodestruction of p. acnes is increased exponentially in an oxygen rich environment.
Various attempts have been made to treat acne with light; Mendes et al. (U.S. Pat. No. 5,549,660) described a method for the light therapy of acne using low intensity red light. Their apparatus was meant to treat acne through it effect on macrophages in the skin. Its low light intensity is not sufficient for an efficient photodynamic destruction of p. acnes in the deeper layers of the skin, High intensity visible light phototherapy for acne was described by Meffert et al, (Dermatol-Monatsschr. 1990; 176(10): 597-603) but they used a light source emitting not only visible light but also UVA comprising up to 15-20% of the total irradiation dose. Sigurdsson et al (Dermatology 1997; 94:256-260), used Philips HPM-10 400 W combined with an UVILEX 390- filter (Desag. Germany) that filters most but not all ultraviolet A (UVA) harmful rays. The spectrum of their lamp peaked at 420 nanometer and had 2 other small peak of emission at 405 and 435 nanometer. Their apparatus emitted at 40 cm; 0.5 J/cm2 of UVA, 20 Jcm2/of violet/blue and 5 J/cm2 of green light.
Basic science research has shown in vitro that the viability of p. acnes relates inversely to light intensity and to oxygen levels to which the p. acnes are exposed. Sigurdsson et al achieved with their apparatus 30% reduction of the total severity of acne and particularly 49% reduction of the number of pustules. The rate of success can be drastically improved by adding and penetrating oxygen to the skin daily and/or immediately before skin exposure to high intensity violet/blue light
According to the present invention there is provided an apparatus and a method for acne phototherapy, achieved by the use of a specially designed apparatus having a narrow spectral band violet/blue light emission with a possible additional spectral line, combined with a pre-treatment application on the treated skin area of an oxygen transporting compounds, based on the use of one or more of the materials from the group of compounds consisting of perfluorocarbons, oxidative substances, keratolytic substances and external photosensitizer such as methylene blue 0.1-5%.
There is thus provided, in accordance with an embodiment of the present invention, apparatus for treatment of a skin disorder. The apparatus includes at least one light source with spectral emittance concentrated in at least one specific narrow spectral band, wherein one spectral band is in the range of 405 to 440 nm, an optical system for collecting and shaping light emitted from the at least one light source and an electronic unit to control parameters associated with the spectral emittance from the at least one light source.
Furthermore, in accordance with an embodiment of the present invention, the parameters include at least one of a group including duration, power and emitted spectral bands of the light source emittance.
Furthermore, in accordance with an embodiment of the present invention, the apparatus further includes a mechanical fixture for holding the light source at an adjustable distance and direction related to a treatment area.
Furthermore, in accordance with an embodiment of the present invention, the illumination energy of the light source flux, is higher than a predetermined threshold level. The threshold level is a level required for biological destruction of acne and seborrhea causing factors.
Furthermore, in accordance with an embodiment of the present invention, the illumination energy threshold level of the illumination light source is at least 40 mw/cm2 at a distance from the light source of 30 cm.
Furthermore, in accordance with an embodiment of the present invention, the illuminated area on a patient body includes an illumination area large enough to illuminate an infected typical size skin area from a fixed position of the light source related to the skin area, In accordance with an embodiment of the present invention The illuminated area is at least 400 cm2.
Additionally, in accordance with an embodiment of the present invention, the apparatus further includes an illumination head having at least two converging collimated beams from at least two directions, each of the beams generated by a separate light source positioned at a distance from the other at least one light source.
Additionally, in accordance with an embodiment of the present invention, the apparatus further includes a computer controlled imaging unit for imaging an illuminated treated area and for monitoring by counting lesions on the treated area, using computerized counting techniques.
Additionally, in accordance with an embodiment of the present invention, the apparatus further includes a computer controlled display unit for displaying the imaged illumination treated area, wherein counting is carried out by an operator marking lesions on the display of the illumination treated imaged surface area. Alternatively, the computer lesions counting by image processing techniques to detect and count each lesion in the illumination treated imaged surface area. The score of the computer lesion counting is recorded in a computer memory to enable monitoring the lesion healing process through a series of consecutive treatments.
Furthermore, in accordance with an embodiment of the present invention, the computer controlled imaging unit idisplay image includes at least one of a group includes a graph of the number of counted lesions versus accumulated treatment time and a table consisting of number of counted lesions in each treatment session.
Furthermore, in accordance with an embodiment of the present invention, the apparatus further includes at least one optical element of a group includes a liquid filled light guide, a solid transparent light guide, a fiber bundle light guide and an array of lenses and mirrors for collecting and conducting the light source radiation and illuminating the skin treated area at an adjustable distance, energy density and direction.
Furthermore, in accordance with an embodiment of the present invention, the light source is a Gallium, Mercury and halides gas mixture discharge lamp with peak emission in the 405-440 spectral band. Alternatively, the light source is selected from the group including Ion Krypton gas laser with a spectral emission in the range 405 to 440 nm, and a diode. The diode is selected from the group consisting of violet/blue laser diodes, and light emitting diodes (LED) with narrow spectral band emission in the range 405-440 nm.
Furthermore, in accordance with an embodiment of the present invention, the light is collected and projected by at least one reflector, wherein the reflector is selected from the group includes of an elliptical cross-section cylindrical reflector, parabolic cross-section cylindrical reflector, and an asymmetric aspheric reflector.
Alternatively, the light is collected and further collimated by a set of two orthogonal cylindrical lenses.
Furthermore, in accordance with an embodiment of the present invention, the light of the at least one light source is collected by an elliptical cross-section reflector having a first focal point and a second focal point. The light source is disposed at the first focal point and has disposed at the second focal point a slit shape aperture of a slit to circular beam shaping and conducting light guide.
Additionally, according to the present invention there is also provided a method of treating a skin disorder. The method includes providing a light radiation source having spectral characteristics of at least one of a group of narrow spectral bands consisting of violet/blue (405-440 nm), red (630-670 nm) and green (520-550 nm) light, applying a compound to a skin area, illuminating the skin area with the light radiation source, and additionally illuminating the skin area after a predetermined time period.
Furthermore, in accordance with an embodiment of the present invention, the skin disorder is one of a group including acne and seborrhea.
Furthermore, in accordance with an embodiment of the present invention, the compound is selected from a group consisting of a topical oxygen transporting perfluoroocarbon, an oxidative agent, a keratolytic agent and a methylene blue solution
Furthermore, in accordance with an embodiment of the present invention, the predetermined time period is at least 24 hours.
Furthermore, in accordance with an embodiment of the present invention, the method further includes a pretreating application of the compound, concentrating the light on the skin area by an optical system and a mechanical fixture, and exposing the skin area at specific time intervals.
Furthermore, in accordance with an embodiment of the present invention, the time interval is 1-5 weekly exposure to violet/blue light for typically 2-10 weeks, with a minimum 24 hour""s time gap between exposures.
Furthermore, in accordance with an embodiment of the present invention, the step of illuminating is accomplished by projecting on the skin area with an illumination power in the range of 10 mW/cm2 to 500 mW/cm2 of violet/blue light radiation.
Furthermore, in accordance with an embodiment of the present invention, the compound is hydrogen peroxide in the concentration of 1-10% by weight and the concentration of salicylic acid is 1-10% by weight.
Furthermore, in accordance with an embodiment of the present invention, pretreating is carried out daily or alternatively immediately before light exposure.
Furthermore, in accordance with an embodiment of the present invention, the material is selected from the group consisting of oxidative and keratolytic compounds is in an aqueous gel. Alternatively, the material selected from the group consisting of oxidative and keratolytic compounds is in oil in water emulsion.
Furthermore, in accordance with an embodiment of the present invention, the oxidative and/or keratolytic compound is within a material selected from the group consisting of a liposome and a positively charged submicron emulsion. Alternatively, the oxidative and/or keratolytic compounds is in a Propylene glycol 10-50% base or an oil in water emulsion mixed with molecular oxygen that is sprayed continuously on the skin before or during light exposure.
Furthermore, in accordance with an embodiment of the present invention, methylene blue 0.1-5% in distilled water or gel bases is applied to the skin before or during light exposure.
It provides a way to increase the photodestruction of p. acnes by providing and illuminating the affected area with high intensity monochromatic, or multi-spectral discrete emission lines light energy, exactly matching the optimal action spectrum of the photosensitizer created by the p. acnes. 
Methylene blue is a dye used parentally for treatment of methemoglobinemia in newborns and topically for disinfecting of skin. In vitro and in vivo studies have shown that Methylene blue may be activated by light to induce a photodynamic reaction. Methylene blue was used for the inactivation of herpes virus helicoabacter pillory and for the experimental therapy of skin bladder and esophageal cancers. The method of photodynamic therapy may also be enhanced by adding an external photosensitizing agent such as methylene blue in a concentration of 0.1-5%.
The proposed method significantly increases the oxygen pressure in the sebaceous glands through the use of oxygen transporting compounds based on perfluorocarbons and/or oxidative emulsions. The proposed method also enhances light and compound penetration into the skin using translucent gels and keratolytic agents. The proposed apparatus emits light energy above a biologic bacteria destruction threshold. The light source generates a high intensity non-coherent light in the exact narrow spectral band or bands, needed for the activation of the photodynamic reaction while filtering out the harmful UV light. This narrow and specific wavelength range radiation enables the administration of sufficient intensity of light to the deeper layers of the dermis without excessive heat formation in the epidermis. The required spectral band is emitted by the present invention light source for the photodynamic destruction of p. acnes in the acne sebaceous glands.